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Full flexibility of the Monge-Ampère system in codimension $d_*-d+1$

Wentao Cao, Jonas Hirsch, Dominik Inauen, Marta Lewicka

Abstract

We prove that $\mathcal{C}^{1,α}$ solutions to the Monge-Ampère system in dimension $d$ and codimension $k= d_*-d+1$, where $d_*$ denotes the Janet dimension, are dense in the space of continuous functions, for every Hölder exponent $α<1$. Our result strengthens the statement in [Lewicka 2022], obtained for $k = 2d_*$ and based on ideas from [Källen 1978] in the context of the isometric immersion system. It also generalizes the result of [Inauen-Lewicka 2025], where full flexibility was established in dimension $d=2$ and codimension $k=2$. The same proof scheme further yields local full flexibility of isometric immersions of $d$-dimensional Riemannian metrics into Euclidean space of dimension $d_* + 1$, generalizing the result in [Lewicka 2025] proved for $d=k=2$. By using techniques of [Conti-De Lellis-Szekelyhidi], the result can be extended to compact manifolds, in codimension $(d+1)d_*-d+1$.

Full flexibility of the Monge-Ampère system in codimension $d_*-d+1$

Abstract

We prove that solutions to the Monge-Ampère system in dimension and codimension , where denotes the Janet dimension, are dense in the space of continuous functions, for every Hölder exponent . Our result strengthens the statement in [Lewicka 2022], obtained for and based on ideas from [Källen 1978] in the context of the isometric immersion system. It also generalizes the result of [Inauen-Lewicka 2025], where full flexibility was established in dimension and codimension . The same proof scheme further yields local full flexibility of isometric immersions of -dimensional Riemannian metrics into Euclidean space of dimension , generalizing the result in [Lewicka 2025] proved for . By using techniques of [Conti-De Lellis-Szekelyhidi], the result can be extended to compact manifolds, in codimension .

Paper Structure

This paper contains 8 sections, 11 theorems, 140 equations, 1 figure.

Key Result

Theorem 1.1

Let $\omega\subset\mathbb{R}^d$ be an open, bounded, $d$-dimensional set. Let the target codimension: Given vector fields $v\in\mathcal{C}^1(\bar{\omega},\mathbb{R}^{\bar{d}})$, $w\in\mathcal{C}^1(\bar{\omega},\mathbb{R}^{d})$ and a matrix field $A\in\mathcal{C}^{r,\beta}(\bar{\omega},\mathbb{R}^{d\times d}_\mathrm{sym})$, assume: in the sense of matrix inequalities. Then, for every exponent $\a

Figures (1)

  • Figure 1: Progression of frequencies, intermediate fields, defects and codimensions used in the proof of Theorem \ref{['thm_stage']}.

Theorems & Definitions (12)

  • Theorem 1.1
  • Corollary 1.2
  • Theorem 1.3
  • Lemma 2.1
  • Lemma 2.2
  • Lemma 2.3
  • Lemma 2.4
  • proof
  • Lemma 2.5
  • Theorem 4.1
  • ...and 2 more